The traditional view of DNA replication is very conservative. The process starts with one double-stranded DNA molecule and produces two identical copies of the molecule. Each strand of the original double-stranded DNA molecule serves as template for the production of the complementary strand.
However, this group of researchers introduced a new idea. Elaborate webs of DNA have been made that can copy themselves outside cells. Unlike DNA in nature, which replicates inside cells, these webs exist freely and suggest how self-replication might one day be an alternative to conventional fabrication for very tiny structures.
A self-copying DNA double-helix would not be news. Living cells have been doing this for billions of years, and researchers have done it in test tubes for decades. But in a new twist, the group has created elaborate webs of DNA never seen in nature and persuaded these structures to make exact copies of themselves.
Each piece of the DNA web is a "tile" made by joining 10 double helices together. The team made two slightly different versions of these tiles, A and B, and joined them together to make a batch of identical strings of seven tiles. These "parent" strings then produced daughter strings made of tiles called A' and B', whose base pairs were exactly complementary to those on the A and B tiles. The researchers used the daughters as a further template to produce an exact copy of their parents
Although these particular strings were designed as a proof of principle, without any practical application in mind, the technique could allow more useful structures to be rapidly and easily grown. Other molecules, with useful or novel properties, could be attached to the DNA tiles. The DNA itself would act as a scaffold, arranging the other molecules into the desired structure, and then later creating more and more copies.
Wang, T., R. Sha, et al. (2011). "Self-replication of information-bearing nanoscale patterns." Nature 478(7368): 225-228.
No comments:
Post a Comment